The present invention relates generally to a tubular polymeric membrane fuel cell system, and more particularly to a tubular fuel cell stack having an integrated manifold.
Fuel cell systems offer many advantages over conventional and other power sources. In particular, fuel cell systems are capable of supplying power at remote locations with minimal maintenance. In a fuel cell, electricity is generated electrochemically through the reaction of hydrogen with oxygen. The only reaction emission involved is water vapor, which is essentially harmless to the environment. This is a stark contrast to a conventional power generation system, which releases harmful emissions such as hydrocarbons, carbon monoxide and other chemicals.
A polymeric electrolyte membrane (PEM) fuel cell system has a solid body electrolyte, typically comprised of a synthetic polymeric material. The polymeric material is a solid body that acts as an electrolyte. The advantage of having a solid electrolyte phase is that there are no operational complications caused by the migration of electrolytic material into adjacent regions of the fuel cell. The system is mechanically stable and is capable of operating under a wide variety of operating conditions.
A natural convection fuel cell system is one in which air, or oxygen, is supplied to a cathode by diffusion from the periphery of the fuel cell. In such a natural convection arrangement, there is no requirement for forced convection through the flowfield to replenish depleted oxygen. Natural convection is preferred over other embodiments because it is less complicated than a forced flow arrangement.
PEM fuel cell power generation systems are ideal for land-based stationary and automotive applications due to the high efficiency, low temperature operation, and negligible harmful emissions in the exhaust gas stream. PEM fuel cell devices are typically modular systems and have extremely flexible designs. However, the complexity and the configuration of the fuel cell stack is a concern for manufacturing and for fuel efficiency, in both automotive and stationary applications.
It is an object of the present invention to provide a polymeric electrolyte membrane (PEM) fuel cell power generation system having reduced power losses and improved reliability. It is another object of the present invention to mechanically integrate a manifold with the fuel cells/fuel cell stacks.
It is a further object of the present invention to provide a manifold that serves as an electrical power lead. It is still a further object of the present invention that the PEM fuel cell system operates under natural convection condition.
In carrying out the above objects and other objects and features of the present invention, a PEM fuel cell system is provided that mechanically integrates a manifold with a fuel cell/fuel cell stack.
The PEM fuel cell engine system of the present invention has a fuel cell stack for the conversion of chemical energy of a fuel gas into electrical energy by an anodic and cathodic electrochemical oxidation/reduction process. The system also has a fuel processor for converting hydrocarbons into a poison free H2 rich gas stream that is suitable for feeding the fuel cells. The system also includes a power conditioning/transfer/control system for transferring power to a system, such as a common household or an automotive drive system. A manifold is mechanically integrated with the fuel cell and provides a power lead to the electrodes in the cell.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.